1. Field of the Invention This invention relates in general to plastic bag packs and, in particular, to a wicketless plastic bag pack and a method for making the pack. More specifically, but without restriction to the particular embodiment hereinafter described in accordance with the best mode of practice, this invention relates to ultrasonic assembly of a wicketless plastic bag pack that utilizes a minimum of disposable shipping materials.
2. Discussion of the Prior Art
The art of assembling bag packs employed in automated industrial bagging operations for packaging products like bread, or other consumer goods, typically involves bundling a stack of bags between two supporting boards with a disposable wicket secured by grommets.
The thermoplastic bags customarily used for packaging consumer products include a bottom edge which may be gussetted, top and bottom walls or front and back walls, depending on the orientation of the bag, a pair of side edges, and an open top end. The material forming the bottom or back wall has a lip portion extending beyond the open end of the bag. A perforated tear line may be formed between the open end of the bag and its lip portion. This tear line allows the bag to be removed from the lip portion as required during bagging operations. The lip portion is also provided with a pair of locating holes. As an alternative to the perforated tear line, top notches may be formed above the locating holes so that the bag may be torn through the notches during the bagging operation. In the assembly process of the bag pack, a U-shaped wicket is inserted through two corresponding locating holes in a first supporting board. As the thermoplastic packaging bags issue off the production line, they are consecutively stacked upon the first support board with their respective locating holes placed over the extending prongs of the wicket. Once a desired number of thermoplastic bags is stacked upon the first board, a second supporting board with corresponding locating holes is placed over the wicket prongs to cover the top of the stack. Rubber grommets are moved down the wicket prongs to securely sandwich the stack of thermoplastic bags between the supporting boards. The bag pack is shipped in this condition to the industrial producer. Bagging equipment utilized by the industrial producer includes a wicket holder for positioning the stack of bags in relation to the production line. Pressurized air is employed to open the next consecutive bag on the pile so that product issuing off the production line is directed into the bag. The filled bag is then removed from the equipment wicket by tearing the bag from its lip portion along the perforated tear line or by tearing through the top notches above the locating holes. When the bagging equipment needs a resupply of bags, an equipment operator removes the rubber grommets and supporting boards from a new bag pack and places the new stack of bags on the wicket holder of the bagging equipment.
Use of this type of prior thermoplastic bag pack involves a waste of packing materials since the rubber grommets, supporting boards, and bag pack wickets are discarded when the stack of bags is mounted on the bagging equipment. In addition to this drawback, costly operator time is required in removing these materials from each bag stack. A further limitation relating to lost time is possible separation of the individual bags from the bag stack. Bagging machine down-time is caused by loose bags which can cause product to miss proper placement into a respective bag. This may result in an unwanted slow-down of the production line. Lastly, industrial producers encounter the cost of disposal in properly storing and hauling away the accumulation of these packing materials.